1. Field of the Invention
The present invention relates generally to digital communication systems, and more particularly, to a character-recognition system for use in a digital mobile communication terminal.
2. Description of the Related Art
As the size of mobile terminals becomes increasingly portable, the operation of such devices has become more difficult for the typical user. The standard keypad is presently capable of providing a variety of functions, however, accessing these functions often requires a user to input a number of key operations, frustrating the user in the process. Moreover, mobile terminals have recently been provided with character data communication service capability as an adjunct to the existing voice capability. As such, additional difficulties arise in that an already overburdened user interface (i.e. keypad) must now serve as the interface for inputting character data in addition to the essential dialing function. Transmitting character data utilizing the limited number of keys on a conventional mobile communications terminal requires a multiplicity of key combinations thus increasing the number of key input operations required of a user. At present, transmitting character data through a conventional mobile communication terminal is carried out in the following three ways. The first way to transmit a message (i.e. character data) is by making a proper combination of key inputs through several key input operations. The second method is to transmit a message previously composed and stored. For example, one of the messages stored in a memory is retrieved for transmission. The third is to make a proper combination of characters displayed on an LCD by operating a specially designed key added to the key pad. Both the first and third methods make it possible to transmit a message as presently composed, but require a large number of key input operations. The second method does not require an inordinate amount of key inputs, however, it is limited in terms of a predetermined content. That is, the message is pre-stored.
Accordingly, it would be highly advantageous to provide methods and an apparatus to facilitate the input of character data in a mobile communication terminal that overcomes the disadvantages inherent in the methods described.
It is therefore an object of the present invention to provide a mobile communication terminal with a character-recognition system for facilitating the input of character data, and a method thereof.
It is another object of the present invention to provide a mobile communication terminal with a touch panel as a character input unit, and a method thereof.
It is still another object of the present invention to provide a mobile communication terminal with a touch pad adapted for users familiar with conventional key pads.
It is still another object of the present invention to provide a mobile communication terminal with a touch panel interface without substantially increasing the size and structural complexity thereof.
It is still another object of the present invention to provide a mobile communication terminal with a touch panel controlled by suitably utilizing the limited number of the chip selection pins of the modem without substantially modifying the internal structure of the mobile communication terminal.
It is a further object of the present invention to provide a mobile communication terminal with a touch panel mounted on the LCD module of its housing.
According to one aspect of the present invention, a character-recognition system provided in a digital mobile communication terminal, comprises a display, a touch panel for generating pressure signals in response to the pressures applied by the characters written on its surface, a touch panel driver for generating coordinate data and touch panel state data calculated from the pressure signals, a character data base for storing character data consisting of shape data and stroke data of the characters, a touch panel drive circuit for generating the addresses of the precise character data retrieved from the character data base by recognizing the data of the written characters, a character code storage for storing the character codes corresponding to the character data stored in the character data base, and a device which comprises a processor functioning as receiving coordinate data and state data from the touch panel drive circuit, outputting the data to a character-recognition means and driving the character-recognition means, receiving the result value of the character-recognition means, reading out the corresponding character code from the character code storage, and displaying them on the display.
According to another aspect of the present invention, a mobile communication terminal including a display, touch panel, character data base for storing character data, and character code storage for storing the character codes corresponding to the character data stored in the character data base, is provided for with a character-recognition method, which comprises the steps of determining whether a character is inputted within a predetermined time interval in character-recognition mode set by an external input signal, comparing the character data input within the predetermined time with character data stored in a character data base, determining whether the character data base contains a character that matches the input character within some pre-defined error range, and display the input character on the display by reading from the character code storage the character code corresponding to the matching character data.
According to still another aspect of the present invention, a character-recognition system provided in a mobile communication terminal, comprises a modem chip, a touch panel for generating X/Y coordinate data representing a pressure trace made by a pen writing on it, and a touch panel driver having a chip selection input pin for receiving a chip selection signal generated from a chip selection output terminal of the modem chip, an X/Y selection terminal for receiving an X/Y selection signal generated from a first general-purpose output terminal of the modem chip and a data transfer terminal for receiving the X/Y selection signal and transferring the X/Y coordinate data through the same data bus from and to the modem chip.
According to a further aspect of the present invention, a display module interface for a character-recognition mobile communication terminal, comprises a modem chip, a display selection circuit for converting the output signal of a general-purpose write output pin provided in the modem chip into a display enable signal, and a display module having an enable terminal for receiving the enable signal, a command/display data input pin for receiving a command/display data selection signal generated from a general-purpose input/output pin of the modem chip, and a data bus for receiving command/display data through the same data bus in response to the command/display data selection signal.